Fluid pump assembly



April 9, 1963 F. e. WEIS 3,084,943

FLUID PUMP ASSEMBLY Filed Oct. 24, 1958 2 Sheets-Sheet. 1

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BY 47TOKN April 9, 1963 F. G. WEIS FLUID PUMP ASSEMBLY Filed Oct. 24,1958 2 Sheets-Sheet 2 E & 8i *i INVENTOR. F1404 6: 14/2/15 BY wATTORNCYr United States Patent 3,084,943 FLUID PUMP ASSEMBLY Frank G.Weis, Kansas City, Mo., assignor, by mesne assignments, to Union TankCar Company, Chicago, L, a corporation of New Jersey Filed Oct. 24,1958, Ser. No. 769,346 2 Claims. (Cl. 277-4) This invention relatesgenerally to the field of fluid pumps and more particularly, to a pumpassembly adapted for utilization in sewage treatment plants with a novelcartridge being provided for enclosing the seal unit mounted on theimpeller shaft of the pump to prevent liakage of sewage from the pumphousing around the s aft.

Fluid pump assemblies of the type commonly employed in sewage treatmentplants normally comprise a pump housing rotatably receiving an impellercarried by a vertical shaft extending from the housing through anaperture therein with the outer end of the impeller shaft being operablycoupled with a prime mover in the nature of an electric motor. Sewageconduits are connected to and communicate with the pump housing in amanner so that upon rotation of the impeller by the motor and throughthe impeller shaft, sewage is caused to flow through the conduits by therotating impeller. In order to prevent leakage of sewage around theimpeller shaft extending outwardly from the housing, it has beenconventional procedure to provide a stuffing box mounted externally onthe housing in surrounding relationship to the impeller shaft andprovided with packing engaging such shaft to preclude leakage of sewagefrom the pump housing through the aperture clearing the impeller shaft.Stuffing boxes of the described type were not entirely satisfactory toprevent leakage of sewage from the impeller housing, not only because ofthe nature of the material handled by the pump assembly but also becauseof the difficulty of properly servicing the stufiing boxes at frequentintervals to prevent leakage of sewage from the pump assembly.

In an attempt to solve the leakage problem referred to above, mechanicalseals have been substituted for the stuffing boxes. Although themechanical seals were superior in certain respects, the leakage problemwas not completely overcome merely by elimination of the stuffing boxesin favor of mechanical seals, because of the difficulty of replacingsuch mechanical seals when the same because worn particularly underfield conditions. Also, the mechanical seals were more expensive thanthe stutfing box type seals and thereby increased the operating cost ofthe system. Replacement of worn mechanical seal units heretoforerequired substantially complete disassembly of the fluid pump and inmost instances included substitution of an entire mechanical seal unitincluding its cartridge in lieu of the worn seal unit and housingtherefor. This operation was time consuming, required shutdown of thepump for an extended period, and often led to severe leakage problemsbecause of the reluctance of operators to replace the mechanical sealsuntil sewage leakage from the pump reached a relatively high level.

It is, therefore, the most important object of the present invention toprovide a substantially permanent, hollow cartridge adapted fordisposition on the impeller housing of the pump in surroundingrelationship to the impeller shaft and configured to receive replaceableseal units for preventing leakage of sewage from the impeller housingaround the aperture clearing the impeller shaft.

It is a further important object of the invention to provide a permanentcartridge for replaceable mechanical seal units and constructed of apair of cup-shaped sections releasably interconnected, whereby removaland reinsertion of a new mechanical seal unit in the cartridge is3,084,943 Patented Apr. 9, 1963 facilitated by virtue of the fact thatit is only necessary to disconnect the two sections of the cartridge,followed by removal of the old seal unit and introduction of a new unit,and the sections of the cartridge again being connected.

Another important object of the invention is to provide an improvedmechanical seal unit cartridge which is adapted to be removably mountedon the impeller housing in surrounding relationship to the impellershaft and enclosing the mechanical seal unit, whereby repair orreplacement of the mechanical seal unit is much easier than inheretofore provided assemblies by virtue of the fact that the cartridgeand associated seal unit therein may be disconnected from the pump andrepaired or over-hauled at a point remote from the pump installation.

Other important objects of the invention include the provision of novelmeans for facilitating removal of the mechanical seal unit cartridgefrom the pump housing; the provision of air bleed off means connected tothe cartridge to permit sealing fluid to readily be introduced into thecartridge containing the mechanical seal unit; the provision ofinterengageable components on the sections constituting the mechanicalseal unit cartridge for assuring accurate coaxial alignment of thesections of the cartridge; the provision of a tapered outer surface onone of the sections serving to facilitate introduction of such sectioninto the aperture of the impeller housing clearing the shaft extendingoutwardly from the same; and other important objects such as theprovision of an impeller shaft having a tapered surface at one endthereof for permitting such shaft to readily be passed through thecomponents of the mechanical seal unit after placement of a new unit inthe sectional cartridge therefor.

In the drawings:

FIGURE 1 is a side elevational view of a fluid pump assembly embodyingthe concepts of the present invention, certain parts being broken awayand in section to reveal details of construction;

FIG. 2 is an enlarged, fragmentary, plan view of the mechanical sealunit cartridge with the impeller shaft extending therethrough insection;

FIG. 3 is an enlarged, fragmentary, side elevational view of thecartridge with parts thereof and the housing receiving the cartridgebeing in section; and

FIG. 4 is a fragmentary, greatly enlarged, vertical, cross-sectionalview through the instant sectional cartridge and illustrating thecomponents of a mechanical seal unit as well as their normal dispositionwithin the cartridge.

A fluid pump assembly adapted for utilization in sewage systems isillustrated in FIG. 1 of the drawings and generally designated by thenumeral 10. Stand 12 of pump 10 mounts a hollow pump housing 14 havingan opening 16 at the lower end thereof normally closed by a mountingplate 18 forming a part of stand 12, a plurality of bolts 20 beingemployed to secure plate 18 of stand 12 to housing 14 in fluid-tightclosing relationship to opening 16. Flange 22 of elbow conduit 24 isjoined to plate 18 by bolts 26 in a position so that conduit 24intercommunicates with housing 14 through central perforation 28 inmounting plate 18. Flange 30 of inlet pipe 32 is bolted to the flange(not shown) of elbow conduit 24 in spaced relationship to flange 22.

A spacer frame broadly designated 34 carried by pump housing 14 inoverlying relationship thereto includes a normally horizontal backheadplate 36 secured to housing 14 in overlying closing relationship to theopening 38 therein, a plurality of bolts 40 being employed to releasablysecure backhead plate 36 and thereby spacer frame 34 to pump housing 14.An annular mounting member 42 forming a part of spacer frame 34 andintegral with a plurality of upright supports 44 removably mounts anelectric motor 46 with a plurality of bolts 48 releasably securing motor46 to member 42. The power shaft 50 of motor 46 is of sufficient lengthto extend downwardly through spacer frame 34 and a central aperture 52and terminating within housing 14, as clearly shown in FIG. 1. Thelowermost end 54 of shaft 50 is tapered and mounts an impeller 56rotatable within housing 14, bolt 58 releasably securing impeller 56 toshaft 50 so that impeller 56 may readily be removed from shaft 50 asdesired. Note that the diameter of impeller 56 is substantially equal tothe diameter of opening 38 to permit removal of impeller 56 from housing14.

A hollow, sectional, mechanical seal unit cartridge broadly numerated 60and constituting the novel improvement of the present invention isreleasably secured to backhead plate 36 in closing relationship toaperture 52 and surrounding impeller shaft 50. Cartridge 60 is adaptedto receive a mechanical seal unit generally designated 62 for preventingleakage of sewage from housing housing 14 through aperture 52.Mechanical seal unit 62 may be conventional in character and preferablyis of the double seal type and thereby includes a pair of centrallyperforated, cup-shaped ceramic rotating seal parts 64 and 66 surroundingimpeller shaft 50 and maintained in spaced relationship by a stainlesssteel coil spring 68 between seal parts 64 and 66. Opposed ends ofspring 68 engage respective resilient O-rings 70 and 72 in turn engagingcorresponding ceramic seal parts 64 and 66. Stationary carbon steel sealrings 74 and 76 are disposed in surrounding relationship to shaft 50 andin engagement with corresponding seal parts 64 and 66, as best shown inFIG. 4. Resilient O-rings 78 and 80 for respective carbon steel sealrings 74 and 76 provide a fluid-tight seal against components ofcartridge 60 in a manner to be more clearly defined hereinafter.

Sectional cartridge 60 is adapted to enclose mechanical seal unit 62 andthereby comprises a normally uppermost section 82 and a lower, similarlyconfigured section 84. Each of the sections 82 and 84 is substantiallycup-shaped and has an end wall 86 provided with a central opening 88 forclearing shaft 50 when cartridge 60 is mounted in position on housing14. Substantially cylindrical side walls 90 are integral with respectiveends walls 86 and extend therefrom, with outwardly extending peripheralflanges 92 being integral with respective side walls 90 in remote,spaced relationship to corresponding end walls 86. Flanges 92 ofsections 82 and 84 are adapted to be disposed in abutting relationshipwith side walls 90 and thereby openings 88 in coaxial relationship whensections 82 and 84 are moved into mechanical seal unit 62 in closingrelationship. Cylindrical surface 94 of side wall 90 of section 84 andadjacent flange 92 thereof is of slightly greater diameter thancylindrical surface 96, which merges relatively smoothly with surface 94through provision of a tapered, intermediate frusto-conical surface 98to thereby facilitate insertion of section 84 into aperture 52 inbackhead plate 36. Note should be taken of the fact that the diameter ofsurface 94 is substantially equal to the diameter of aperture 52,whereby section 84 frictionally engages backhead plate 36 and sealsaperture 52.

The inner cylindrical surfaces 85 of each of the sections 82 and 84 andextending inwardly from respective flanges 92 are of greater diameterthan carbon seal rings 74 and 76 to permit easy insertion of the latterinto corresponding sections 82 and 84. Innermost cylindrical surfaces 87adjacent respective end walls 86 have a diameter less than that ofsurfaces 85 and substantially equal to the outer diameter of rings 74and 76 and thereby serving to maintain the latter in coaxial alignmentwith openings 88. Surfaces 85 merge smoothly with surfaces 87 throughtapered intermediate inner faces 89 which guide rings 74 and 76 intorespective innermost ends of sections 82 and 84 during assembly of themechanical seal unit 62.

The normally uppermost end of side wall of section 84 is provided withan internal, annular recess 100 adapted to complementally receive anannular extension 102 projecting outwardly from side wall 90 of section82 in coaxial relationship with the defined side wall. Extension 102 andrecess 100 cooperate to maintain sections 82 and 84 in alignment withthe openings 88 thereof in coaxial relationship.

A number of relatively short stud bolts 104 arranged circumferentiallyaround flanges 92 of sections 82 and 84 extend through flange 92 ofsection 82 and are threadably received in flange 92 of section 84 forreleasably interconnecting sections 82 and 84. A plurality of bolts 106substantially longer than bolts 104 and spaced between the latter extendthrough the flanges 92 of both sections 82 and 84 and are threaded intobackhead plate 36 for removably securing cartridge 60 to plate 36 inclosing relationship to aperture 52. The lower face of flange 92 ofsection 84 engages plate 36 when cartridge 60 is mounted in its normalposition on plate 36.

A fluid bleed off line 108 is connected to and communicates with section82 adjacent the normal point of interengagement of carbon steel sealingring 74 and ceramic sealing part 64, while a manually controlled screwvalve 110 is threaded into coupling 112 on the outermost end of line108. Tubular valve element 114 complementally threaded into coupling 112has a valve seat 116 receiving screw valve 110. A fitting 118 threadedover the outer end of tubular element 114 threadably receives screwvalve 110 and is provided with an orifice 120 for permitting escape offluid therethrough upon movement of valve 110 away from seat 116. Aliquid supply conduit 122 coupled with section 82 in spaced relationshipto line 108 serves to direct a sealing liquid into the interior ofcartridge 60.

It is preferred that an annular gasket 124 be provided between flanges92 of sections 82 and 84 to prevent leakage of sealing liquid betweenflanges 92 upon introduc tion of liquid into cartridge 60 throughconduit 122.

During initial assembly of the present fluid pump assembly 10, thecomponents of mechanical seal unit 62 are placed within sections 82 and84 and bolts 104 are passed through flange 92 of section 82 and threadedinto flange 92 of section 84 to releasably interconnect sections 82 and84 with gasket 124 compressed between corresponding flanges 92.Thereupon, shaft 50 with the impeller 56 removed therefrom is passedthrough openings 88 in sections 82 and 84 and thereby the annularcomponents of mechanical seal unit 62, and then impeller 56 is securedto tapered end 54 of shaft 50 by bolt 58.

It is to be understood, however, that prior to emplacement of impeller56 on shaft 50, backhead plate 36 is slipped over the lower end 54 ofshaft 50 and moved into a position with section 84 telescoped withinaperture 52 and surface 94 of section 84 frictionally engaging plate 36.At this time, bolts 106 are preferably passed through flanges 92 ofsections 82 and 84 and threaded into backhead plate 36 to releasablysecure cartridge 60 to such plate. Joinder of motor 46 to spacer frame34, connection of plate 36 to housing 14, and bolting of stand 12 to thelower end of housing 14 completes the assembly operation.

Since the components of mechanical seal unit 62 form no part of theinstant invention, the operation of the same will not be described indetail, but it is to be pointed out that O-rings 78 and 80 provide aseal between carbon seal rings 74 and 76 and sections 82 and 84, whileO-rings 70 and 72 engaging shaft 50 provide an effective seal betweenthe latter and ceramic sealing parts 64 and 66. Coil spring 68 engagingO-rings 70 and 72 and forcing ceramic sealing parts 64 and 66 intocontacting relationship with carbon steel sealing rings 74 and 76 servesto eflect a seal between parts 64 and 66 and rings 74 and 76respectively.

Upon connection of fluid pump assembly to pipe 32, as well as an outletconduit, valve 110 is rotated in a direction to move the same away fromvalve seat 116 and thereby intercommunicate the interior of cartridge 60with the atmosphere. Next, liquid is directed into the interior ofcartridge 60 through conduit 122 to provide an effective seal duringrotation of shaft 50 by motor 46. As soon as cartirdge 60 is completelyfilled with liquid, as indicated by overflow of the same through orifice120, valve 110 is rotated in a direction to move the same intoengagement with seat 116 and thereby closing line 108. A small quantityof liquid contained within cartridge 60 may leak therefrom aroundO-rings 78, 80, 70 and 72 during operation of pump assembly 10 and thus,it is desirable that a source of liquid be connected to conduit 122 forcontinuously applying a pressure on the liquid within cartridge 60.Various sources of supply conventional in this field may be connected toconduit 122, the most convenient being a by-pass line from housing 14and including a filter therein (not shown) for removing solid particlesfrom the sewage liquid prior to passage of the same into conduit 122.

When it is desired to remove cartridge 60 from backhcad plate 36 toclean the components of mechanical seal unit 62 or to replace the same,cartridge 60 may readily be displaced from aperture 52 by first removingbolts 104 from flanges 92, then unscrewing bolts 106 from backhead plate36 and placing the same in the openings previously occupied by bolts104. Rotation of bolts 106 in the openings normally receiving bolts 104,in a direction to move the lower ends of bolts 106 into engagement withplate 36, forces flange 92 of section 84 and thereby both sections 82and 84 in a direction away from plate 36. After surface 94 of section 84has been shifted out of frictional engagement with plate 36 withinaperture 52, cartridge 60 may readily be removed from spacer frame 34.It is to be understood, of course, that conduit 122 has been previouslydisconnected from section 82 to permit movement of cartridge 60 relativeto frame 34.

With cartridge 60 completely removed from assembly 10, the components ofmechanical seal unit 62 may be cleaned or replaced at a convenientlocation. In this manner, the delicate seal parts may be handled withoutdamage to the same and while being installed on the much larger pumpassembly, an operation very difficult to perform with other mechanicalseal units not having a sectional cartridge 60 as provided in theinstant invention. Also, as indicated above, the tapered end 54 of shaft50 facilitates insertion of the latter in mechanical seal unit 62 andpassage of the same through opening 88 in sections 82 and 84 withoutdamage to the delicate seal components.

By utilization of cartridge 60, the cost of replacement of themechanical seal unit is materially reduced and maintenance operationsare simplified, thereby decreasing operational cost of pump assembly 10.

Having thus described the invention what is claimed as new and desiredto be secured by Letters Patent is:

1. In a fluid pump assembly having a hollow housing provided with anaperture, a power driven impeller shaft extending into the housing and amechanical fluid seal unit around the shaft externally of the housingand including a pair of annular seal parts surrounding the shaft androtatable therewith, and normally stationary seal ring means surroundingthe shaft and in engagement with opposed outer surfaces of respectiveseal parts, the combination with said assembly of:

a sectional, hollow seal unit cartridge including a pair of permanent,substantially identical, cup-shaped sections each having a circular endwall provided with an opening clearing a proximal portion of the shaft,central, cylindrical wall portions coaxial with the shaft and spacedtherefrom, and an outwardly extending, peripheral flange integral with arespective cylindrical wall portion and remote from corresponding endwalls, said flanges on said sections having aligned openings therein,the openings in the flanges of one of said sections being internallythreaded;

first and second bolts having the same diameter but with the secondbolts being shorter than said first bolts, said first and second boltsextending through the openings in the flange of the other section andbeing threaded into the openings of said one section for releasablyinterconnecting said sections with the flanges in abutting coaxialrelationship and with said openings of said end walls in alignment theouter ends of the threaded portion of said first bolts extendingoutwardly from the other section and engaging the housing, said firstbolts being of sufficient length to force said one section out of theaperture and thereby to move the cartridge away from the housing as thehead ends of the first bolts are moved toward the flange of the othersection;

structure removably mounting the cartridge on the housing in a positionsurrounding the shaft, completely enclosing the seal unit with one ofthe sections telescoped within the aperture in closing relationshipthereto and the shaft extending through said openings in the sections,said cartridge receiving said seal unit in a position with the seal ringmeans engaging corresponding sections to preclude rotation of said sealring means as the seal parts are rotated with said shaft, thecylindrical side wall portion of said one section having an outer,circumferentially extending, tapered surface of a width to facilitateinsertion of said one section into said aperture; and a liquid supplyconduit connected to the other section of the cartridge.

2. In a fluid pump assembly having a hollow housing provided with anaperture, a power driven impeller shaft extending into the housing and amechanical fluid seal unit around the shaft externally of the housingand including a pair of annular seal parts surrounding the shaft androtatable therewith, and normally stationary seal ring means surroundingthe shaft and in engagement with opposed outer surfaces of respectiveseal parts, the combination with said assembly of:

a sectional, hollow seal unit cartridge including a pair of permanent,substantially identical, cup-shaped sections each having a circular endwall provided with an opening clearing a proximal portion of the shaft,central, cylindrical wall portions coaxial with the shaft and spacedtherefrom, and an outwardly extending, peripheral flange integral with arespective cylindrical wall portion and remote from corresponding endwalls, each of the sections being provided with a first innercylindrical surface adjacent the flange thereof of greater diameter thana second cylindrical surface disposed in proximal relationship to theend wall of a respective section and adapted to complementally receivecertain components of the seal unit, there being an inner, intermediate,tapered face interconnecting said first and second surfaces on each ofthe sections for guiding said components into the recess defined byrespective second cylindrical surfaces and a corresponding end wall ofthe sections;

removable bolt means extending through the peripheral flange of onesection and threaded into the flange of the other section for releasablyinterconnecting said sections with the flanges in abutting coaxialrelationship and said openings in alignment;

structure removably mounting the cartridge on the housing in a positionsurrounding the shaft, completely enclosing the seal unit with one ofthe sections telescoped within the aperture in closing relationshipthereto and the shaft extending through said openings in the sections,said cartridge receiving said seal unit in a position with the seal ringmeans engaging corresponding sections to preclude rotation of said sealring means as the seal parts are rotated with said shaft, thecylindrical side wall portion of said one section having an outer,circumferentially ex- 5 tending, tapered surface of a width tofacilitate insertion of said one section into said aperture; and

liquid supply conduit connected to the other section of the cartridge.

References Cited in the file of this patent UNITED STATES PATENTS MartinDec. 14, 1897 Drew Oct. 12, 1920 Durdin June 14, 1932 Morton Sept. 27,1932 Arutunoff Aug. 23, 1949 Peguet et al Mar. 10, 1959 Gilbert Aug. 30,1960

1. IN A FLUID PUMP ASSEMBLY HAVING A HOLLOW HOUSING PROVIDED WITH ANAPERTURE, A POWER DRIVEN IMPELLER SHAFT EXTENDING INTO THE HOUSING AND AMECHANICAL FLUID SEAL UNIT AROUND THE SHAFT EXTERNALLY OF THE HOUSINGAND INCLUDING A PAIR OF ANNULAR SEAL PARTS SURROUNDING THE SHAFT ANDROTATABLE THEREWITH, AND NORMALLY STATIONARY SEAL RING MEANS SURROUNDINGTHE SHAFT AND IN ENGAGEMENT WITH OPPOSED OUTER SURFACES OF RESPECTIVESEAL PARTS, THE COMBINATION WITH SAID ASSEMBLY OF: A SECTIONAL, HOLLOWSEAL UNIT CARTRIDGE INCLUDING A PAIR OF PERMANENT, SUBSTANTIALLYIDENTICAL, CUP-SHAPED SECTIONS EACH HAVING A CIRCULAR END WALL PROVIDEDWITH AN OPENING CLEARING A PROXIMAL PORTION OF THE SHAFT, CENTRAL,CYLINDRICAL WALL PORTIONS COAXIAL WITH THE SHAFT AND SPACED THEREFROM,AND AN OUTWARDLY EXTENDING, PERIPHERAL FLANGE INTEGRAL WITH A RESPECTIVECYLINDRICAL WALL PORTION AND REMOTE FROM CORRESPONDING END WALLS, SAIDFLANGES ON SAID SECTIONS HAVING ALIGNED OPENINGS THEREIN, THE OPENINGSIN THE FLANGES OF ONE OF SAID SECTIONS BEING INTERNALLY THREADED; FIRSTAND SECOND BOLTS HAVING THE SAME DIAMETER BUT WITH THE SECOND BOLTSBEING SHORTER THAN SAID FIRST BOLTS, SAID FIRST AND SECOND BOLTSEXTENDING THROUGH THE OPENINGS IN THE FLANGE OF THE OTHER SECTION ANDBEING THREADED INTO THE OPENINGS OF SAID ONE SECTION FOR RELEASABLYINTERCONNECTING SAID SECTIONS WITH THE FLANGES IN ABUTTING COAXIALRELATIONSHIP AND WITH SAID OPENINGS OF SAID END WALLS IN ALIGNMENT, THEOUTER ENDS OF THE THREADED PORTION OF SAID FIRST BOLTS EXTENDINGOUTWARDLY FROM THE OTHER SECTION AND ENGAGING THE HOUSING, SAID FIRSTBOLTS BEING OF SUFFICIENT LENGTH TO FORCE SAID ONE SECTION OUT OF THEAPERTURE AND THEREBY TO MOVE THE CARTRIDGE AWAY FROM THE HOUSING AS THEHEAD ENDS OF THE FIRST BOLTS ARE MOVED TOWARD THE FLANGE OF THE OTHERSECTION; STRUCTURE REMOVABLY MOUNTING THE CARTRIDGE ON THE HOUSING IN APOSITION SURROUNDING THE SHAFT, COMPLETELY ENCLOSING THE SEAL UNIT WITHONE OF THE SECTIONS TELESCOPED WITHIN THE APERTURE IN CLOSINGRELATIONSHIP THERETO AND THE SHAFT EXTENDING THROUGH SAID OPENINGS INTHE SECTIONS, SAID CARTRIDGE RECEIVING SAID SEAL UNIT IN A POSITION WITHTHE SEAL RING MEANS ENGAGING CORRESPONDING SECTIONS TO PRECLUDE ROTATIONOF SAID SEAL RING MEANS AS THE SEAL PARTS ARE ROTATED WITH SAID SHAFT,THE CYLINDRICAL SIDE WALL PORTION OF SAID ONE SECTION HAVING AN OUTER,CIRCUMFERENTIALLY EXTENDING, TAPERED SURFACE OF A WIDTH TO FACILIATEINSERTION OF SAID ONE SECTION INTO SAID APERTURE; AND A LIQUID SUPPLYCONDUIT CONNECTED TO THE OTHER SECTION OF THE CARTRIDGE.